Long Term Evolution (LTE) is a LTE of an Universal Mobile Telecommunications System (UMTS) technology standard developed by a 3rd Generation Partnership Project (3GPP). Under a guidance of this evolution plan, a new mobile communication network architecture is defined, namely, a System Architecture Evolution (SAE) network architecture. FIG. 1 is a schematic diagram of a mobile communication network architecture according to a first example in the related art. As shown in FIG. 1, the following network elements are included:
an Evolved Wireless Access Network (E-RAN), which can provide higher uplink and downlink rates, lower transmission delay and more reliable wireless transmission, in which a network element included in the E-RAN is an Evolved NodeB (eNodeB), which provides radio resources for an access of a terminal;
a Home Subscriber Server (HSS), which permanently store user contract data;
a Mobility Management Entity (MME), which is a control panel functional entity, temporarily storing a server of user data, responsible for managing and storing UE contexts (such as an UE identity, a user identity, mobility management status, user security parameters, etc.), assigning a temporary identity for the user when an UE is stationed in a tracking area or a network is responsible for authenticating a user; processing all non-access layer messages between the MME and the UE; and triggering aging on the SAE;
a Serving Gateway (GW), which is a user plane entity, responsible for routing and processing user plane data and terminating downlink data of the UE in a idle state, managing and storing an SAE bearer context of the UE, such as IP bearer service parameters and network internal routing information, and the like, in which the GW is an anchor of a user plane inside a 3GPP system, and the user can only have one Serving GW at a time;
a Packet Data Network Gateway (PDN GW), which is a GW responsible for the UE accessing the PDN, assigning the IP address for the user, and being used as a mobile anchor of the 3GPP and a non-3GPP access system at the same time, in which the user can access multiple PDN GWs at the same time; and
a Policy and Charging Rule Functionality Entity (referred to as PCRF), which generates a Quality of Service (Qos) rule and a charging rule for controlling user data transfer mainly according to service information and user contract information and operator configuration information and can also control the establishment and release of the bearer in the access network.
FIG. 2 is a schematic diagram of a mobile communication network architecture according to a second example in the related art. As shown in FIG. 2, a plurality of MME network elements in the SAE network may constitute a POOL, and an MME POOL area indicates that the UE does not need to change a area serving the MME. One MME POOL area has one or more peer MMEs, and an eNB within the MME POOL area is connected to each MME.
By setting up MME POOL, when the UE moves within the MME POOL area, it is not necessary to switch an MME node, which can effectively reduce signaling interaction between systems. In the POOL, users can be distributed in various MMEs in a balanced manner, ensuring a consistency of a load on each MME within the POOL and a processing capacity of each MME. At the same time, if the processing capacity of each MME changes, all or part of the users in the MME can be unloaded to other MMEs through a load unloading. After a MME is not available in the POOL, other MMEs in the POOL can take over the users under a faulty MME.
When a certain MME performs load unloading, the users in this MME will be unloaded into the POOL or in an MME outside the POOL for distribution based on a weight, and the users in this MME cannot be migrated to a specified MME.
There is no valid solution for a problem that a user in an MME cannot be migrated to another specified MME in the related art.